Novak Djokovic admits he was flattered to discover Andy Murray and his coach Ivan Lendl are working overtime to end his two-year reign as Wimbledon champion.

Serbia's Novak Djokovic in action during his match with Belgium's David Goffin.(AP Photo)

Novak Djokovic admits he was flattered to discover Andy Murray and his coach Ivan Lendl are working overtime to end his two-year reign as Wimbledon champion.

Djokovic holds all four Grand Slam titles after winning the French Open earlier this month and the world number one is heavily favoured to defend his crown at the All England Club.

Murray has been Djokovic’s most consistent rival over the last six months, but the Serb has won 13 of their last 15 meetings, including at the Australian and French Open finals this year.

It was that failure to get the better of Djokovic which played a key role in the world number two’s decision this month to reunite with Lendl, who was Murray’s coach when he defeated Djokovic in the 2013 Wimbledon and 2012 US Open finals.

Lendl announced his return to the fray by claiming he and Murray would do all they could do end Djokovic’s spell as the preeminent force on the men’s tour.

“It’s flattering to hear that,” Djokovic said. “I know there’s been a lot of talk about a potential match-up between Andy and me, and with Ivan coming to his team, but it’s still very early.